Re: [boost] Shared_ptr "mini garbage collector"

From: Peter Dimov (pdimov_at_[hidden])
Date: 2003-01-07 17:33:56

From: "David Abrahams" <dave_at_[hidden]>
>
> Yes, but IIUC the reason the library's not doing it is because you
> might get the order wrong, which could cause a problem like a dangling
> pointer needed for some destructor.

Not really... The library's not currently doing it because it hasn't been my
goal to provide a "real" garbage collected pointer. sp_debug_hooks.cpp is an
example that demonstrates what can be done with the debug hooks called by
shared_ptr; code using it operates in "safe mode" (or slightly safer mode.)
IOW a shared_ptr cycle is still not supposed to happen in bug free programs.

That aside, can you think of a reasonable design that does not depend on
intentionally created shared_ptr cycles, but still needs a correct
destruction order when a cycle is broken?